Oxazoeidones and erocesstok



Patented Mar. 9, 1948 reifer;

OXAZOLIDONES ANDI PRIOCESS'FOR MAKING THE' SAME wAugust; H. Homeyer, Webster- Groves, Mo.,'1as Asignor 4to Mallinckrodt f Chemical rWorks, St.

Louis, Mio., a corporation ufl-Missouri i"No Drawing. Original application February 13,

-1942,`Seria1'fNo.430,741. Divided-and this applicaticn; February 16, 1946, VSerial Nor 648,207

.This invention relates to rive-membered :ring

compounds, and moreyparticularly, to A2-oxazolidones.

This application is a divisionof my copending `applicationiSerial No. 430,74l,;iiled February 13,

Y:Among .theobjects of this invention arefthe preparation of new-compounds ofthe Z-oXazoli- K done'series; theprovision of aconvenientmethod for making 2-oxazo1idones; andthe provision of an improved method for the economical preparation of compounds of thistype. Other objects will be in part obvious and' in partY pointed out fp-hereinafter. Y

.The invention accordingly comprises, the y ingredients anfdvcombinations ofv ingredients, the vproportions thereof, steps and sequence of steps, and features ofcomposition; and :'synthesiazanal- Y yss, .or imetathesis, which will :beY .exemplified in f ;the-productsii and processes .hereinafter described, `and the scope of the applicationof fwhichwill .be :indicated inn the yfollowing claims.

According to.thepreserit invention, Zeoxazoldones are ,prepared by ,the reactionzof 'a -amino :alcohol ,fand an yalkyl carbonate. "Theireaction :,mays'be: representedby theifollowing equation:

y v'Inmany instancesa small amountofacatalysu` .Unsyi'nmetrical Y Y* 19 Claims. (Cl. 260-307) consisting Otan alkalinemetallic compound, is

.necessary tocause the reaction to take place at ordinarily available conditions. Suitable -catalysts are,V for example, sodium'methylate, `rmagnesium ',methylate,v potassium-hydroxide `andfsodium Acarbonataalthough other alkaline-metallic compoundscmayzbe substituted. Although the function of the catalyst hasrnot been-completely determined, it is believe'dfthat theactiveelement however, "be -made' to undergo-furtherreaction with the alkyl carbonate where an Vadditional functional group is present to'- give more complex products.

'The reaction materialsy must 1loefree-of #moi-s- *ture Ibefore theereac'tion-'Willbegin. The-system may Ylbe'dried conveniently by distilling off moist alkyl carbonates, -or by addingtoluene and distilling off a mixture of toluene and Water. Other methods may also be employed to remove moisture fromthefsystem',

-Wherever the term alkyl appearsft-Will be understood that cycloalkyl radicals or compounds 30l or faryl appears,v it -will .be understood 'thatsub- 1, stituted iallyls Vor aryls .-,are likewise suitabla as are included. `lllikevviseWhere theterm alkyl are aralkyls.

The Yfollowing examples illustrate ithe L.invention:

"EXAMPLE 1 Ethanolamine -A three-neckediask was tted: Witnazmechanical stirrer and an efficienti'fractonatingzcolumn Ethanolamine (61 ,gJ, diethyl carbonate (150 mL), and sodium methylate (0.5 g.) were placed in the ask. "-The reaction mixture was stirred andthe flask. .was .heated Vin an .oil bath. Y. As the reaction progressed, alcohol Wasformed and was removedas distillate at f they head of 'the column. Atotal of 112 ml. of.alcohol,.corresponding to two v.moles per ,mole of ethanolarnine, Wasobtained. Thevresidue in the ask solidiiiedon` cooling; -it

Wasrecrystallized Yfrom 100 ml. oihloroorm.

Y yTwo crops of..2-.oxazolidone Were obtained, lWeighingatotal of 57g., andrepresentng 65%.i0'fjthe theoretical yield. :The product melted at '87- 89. C. c

2-.oxazolidone (3 .g.) wascacetylated by" boiling ing with acetic anhydride (20 ml.) and sodium acetate (1 g.) for 1.5 hours. Excess acetic anhydride was distilled off under reduced pressure and the residue was recrystallized from a mixture of benzene and ether. After sublimation in a high vacuum at 65 C. the pure 3-acetyl-2-oxazolidone melted at 69-70 C. It was soluble in water and its solution was neutral to litmus. Analysis of the new compound gave 10.9%'nitrogen, compared to the theoretical calculated for CsH'zOsN of 10.85%.

Boiling 2-oxazolidone (9 g.) with acetyl chloride (11 m1.) for one hour was accompanied by the evolution of hydrogen chloride. Recrystallization of the residue from a mixture of benzene and ether gave the 3-acetyl derivative which was identical with the product obtained by the action of acetic anhydride.

EXAMPLE 2 Z-amino-Z-methyl-Z-propanol Z-amino-Z-methyl-l-propanol (89 g.) and diethyl carbonate (210 ml.) were placed in the apparatus described in Example 1. The system was dried by distilling 01T moist diethyl carbonate (40 ml.) The flask was cooled and so-dium methylate (0.5 g.) was added as a catalyst, and then heating was continued. As the reaction progressed, alcohol was formed and a total of 115 ml. was obtained as distillate. Excess diethyl carbonate was removed by distillation under reduced pressure. The residue solidied on cooling. The

product was purified by recrystallization from a mixture of alcohol and petroleum ether. The yield of 4,4-dimethyl-Z-oxazolidone was 83 g. or '72% of the theoretical. The product melted at 55-56 C., and was very soluble in water, alcohol or benzene. Analysis of the new compound gave 52.2% carbon, 7.9% hydrogen, and 12.2% nitrogen, compared,` to the theoretical calculated for CsHsOzN of 52.2%, 7.8% and 12.2% respectively. Determination of the molecular weight gave 112, compared to the theoretical of 115.

EXAMPLE 3 Z-amz'no-Z-methyl-I -popanol Z-amino-Z-methyl-l-propanol (89 g.) and din-propyl carbonate (260 g.) were combined in the apparatus described in Example 1, and the system was dried by distilling under 135 mm. 'pressure until 40 g. `of dipropyl carbonate had been collected. A solution of magnesium methylate (0.5 g.) in methyl alcohol (15 ml.) Was added, a rapid reaction occurred and methyl alcohol (15 ml), followed by propyl alcohol (122 ml.) were collected as distillate in 35 minutes. From the residue a good yield of 4,4-dimethyl-2- oxazolidone, identicall with the product produced in Example 2, was obtained. l

EXAMPLE 4 Z-amino-I -butanol 2-amino-1-butanol (89 g.) and diethyl carand petroleum ether by cooling with solid carbon dioxide. The yield of 4ethyl2oxazolidone was 57 g. It'melted at 16-16.5 C. and its index of refraction was nD20 1.4631. The product was very soluble in water and the solution was neutral to litmus.v Analysis of the new compound gave 52.1% carbon, 7.8% hydrogen and 12.3% nitrogen, compared to the theoretical calculated for C5H9O2N yof 52.2%, 7.8% and 12.2% respectively.

i EXAMPLE 5 2-amzno-3-heanol 2-amino-3-hexanol (60 g.) and diethyl carbonate (350 ml.) were placed in the apparatus described in Example 1, and the system was dried by distilling until 50 ml. of diethyl carbonate had been collected. Sodium methylate 1 g.) was added as a catalyst and heating was continued until 55 ml. of alcohol had been collected as distillate. The reaction mixture was iiltered, excess diethyl carbonate was removed by distillation under reduced pressure, and the residual oil was fractionated through an indented column. 4-methyl- 5-propyl-2-oxazolidone was an oil which boiled at 133 C. at 1.5 mm. pressure and its index of refraction was nD20 1.4581. The yield was 62 g. Analysis of the new compound gave 58.8% carbon, and 9.0% hydrogen, compared to the theoretical calculated for C'zHiaOzN of 58.7% and 9.1% respectively.

EXAMPLE 6 Diethanolamine Diethanolamine g.) diethyl carbonate g.), and sodium methylate (0.5 g.) were placed in the apparatus described in Example 1, and heated at atmospheric pressure. Alcohol was formed as the reaction progressed, a total of 115 ml. being collected in 1.25 hours; this'corresponds to two moles of alcohol per mole of diethanolamine. Excess diethyl carbonate was removed by distillation under reduced pressure. The residue of crude 3-(2-hydroxyethyl) -2-oxazolidone Wasa Viscous liquid which was soluble in water and insoluble in ether. A sample was puried by molecular distillation in a high vacuum at about 175 C. Analysis of the new compound gave 46.0% carbon, and 6.7% hydrogen, compared to the theoretical calculated for C5II9O3N of 45.8% and 6.9% respectively.

A sample of the product (3.5 g.) ,was dissolved in a little chloroform and phenylisocyanate (2.8 g.) dissolved in ether was added. The solvents were boiled oil and the residue was recrystallized from benzene. The phenyl urethane of 3-(2- hydroxyethyl) -2-oxazolidone melted at lOl-102 C. Analysis of the new compound gave 11.2% nitrogen, compared to the theoretical calculated fOr C12II14O2Nz of 11.2%.

3-(2-hydroxyethyl) -2-oxazolidone (2.5 g.) and benzoyl chloride (2.5 ml.) were heated at 100 C. until hydrogen chloride was no longer evolved. The product was crystallized from methyl alcohol by cooling in solid carbon dioxide and then from a mixture of methyl alcohol and ether. It was sublimed in a high vacuum at C. The benzoate of 3'- (2 hydroxyethyl) 2 loxazolidone melted at 69-70 C. Analysis of the new compound gave 5.95% nitrogen, compared to the theoretical calculated for C1zH13O4N of 5.95%.

EXAMPLE 7 Z-amz'nO-l -phe'nyl-I -propanol 2-amino-1-phenyl-l-propanol (50 g.) and diethyl carbonate (350 ml.) were placed in the apliquid which solidified on cooling. vcrystallized from benzene and washed with ether.

vl`was 17g. or 89% of the theoretical.

ether. litmus. Analysis gave 7.3% nitrogen, compared .feg/137,389

,.paratus". described in Example 1, `and' the. system :was dried by distillinguntil 25 ml. diethyl vcarlbonate hadbeen collected. Sodium methylate (1g.) was added and heatingwas continued unvtil 38 ml. of alcohol had beenobtained as distillate. The reaction'mixture was filtered and Qexcessdiethyl carbonate was removed by distil- .flation under reduced pressure.

:dissolved in chloroform and mixed with petrole- The residue was um ether. The solid which separated weighed .21.g. `After removing the solvent romthe` mother liquor, the residue was a viscous oil which Vweighed 37 g. rhe solid and theoil thus obtained represent diastereomeric mixtures of 4- methyl-5-phenyl-Z-oxazolidone. The solid prod- `uct Was'recrystallized from a mixture o Ychloroform and petroleum ether and then from ben- After sublimation in a high vacuum at 130 yC., theproductmelted at 96-98 C.` Analysis of the new product gave 67.9% carbon,'6.0% hydrogengandr 8.0% nitrogen, compared to the theoreticaloalculated for CioHnOzN of 67.8%,

, 6.3% and 7.9% respectively.

Thesolid,-melting at 96498 C., was dissolved in about parts of warm benzene andV allowed to crystallize. The solid which 'separated was recrystallized, and then subllmed in a high vacuum. The product, amixture of the 2-oxazolidones derived from the isomers of 2-amino-1- Vphenyl-1-propanol, melted at M15-147 C. Analysis of the new product gave '7.96% nitrogen, compared to the theoretical calculated for EXAMPLE 84 Ephedrne Ephedrine alkaloid (16.5 g.) and dipropyl carbonate (40 g.) were placed in the apparatus described in Example 1, and the system was dried by distilling at a pressure of 100 mm. until 15 m1. of dipropyl carbonate had been collected.

:Sodium methylate (0.2 g.) was added and the reaction mixture was heated at atmospheric pressure in an oil bath at 160 C.V The temperature -of the reaction mixture was about 131 C., and Y14 m1. of propyl alcohol, B. P. 95 C., were collected as distillate. 'duced Ato 100 mm. and theexcess dipropyl car- Then'the pressure was rebonate was distilled off. The residue ywas a 1t was re- -The lyield of 3,4-diethyl45-phenyl-2oxazolidone The `'product melted at 90-92 C., sublimed in a highfvacuurn at 90 C., was soluble in chloroformY or benzene, and less soluble in water or AThe solution in water was neutral to tothe theoretical calculated for C111I13O2N of 7.3%. The compound was levo rotatory, [@1927 be- Vving --95 when 0.6563 g. of the substance was made up to' 25 ml. of solution with 95% alcohol.

' EXAMPLE 9 l 2amino-2methyl-1,3propanediol 2-amino-2-methyl1,3x propanediol (52.5 g.)

`and diethyl carbonate (59 g.) were placed in the apparatus describedin Eixample 1 and heated by an oil bath. Aloohol'began to be collected at the A head vof the column when the temperature of the 1reaction mixture was 120 C. A total of 44 g.

ofalconol was collected as distillate in two hours.

VAt the end 'of the heating period, 'thetempera-Y f turerfofthe; reaction v'.-fmixture .179 C. Lf.The

- product-:solidifle'd :on cooling VIt weighed 265, g.

.fRecrystall-ization :from anhydrous alcohol l('75 ml.) .fg-avefarst :crop welghingl 50l :gaandxa lseconderop weighing 14g. `.'1`he'pure 4-,methyl-4- hydroxmethyleZeoxazoldonermeltedfat-.l154116.5"

'.C. The product :sublimed' .lnfahigh vacuum fat -135"-1C.` It'".was soluble. 'in-v waterzand l.the .solution Was'zneutrallftoilitmus. Analysisoflthe .newoomlpound J gave 46.0% carbon, .6.7 l'.hydrogen, .and ;10;7.% ;.nitrogen;. compared fto the theoretical calculated for C5H9O3N of 45.8%,l699 .an`d,10.7% respectively.

A sample of the productV (4.4 g.) was mixed with phenylisocyanateKGml.) *and heated at 100 Gi-fbi- 1-.5 hours. The '..productsolidifled onfcoolingand was Yrecrysta'llizedl Vfrom-a mixture of chloroform and-ether. YThe 'phenyl urethane `of y4- Y vmethyl-i4--hydroxymethyl-Z oxazolidone melted fat 13B-i134 C. It iwas soluble. in.l methyl alcohol, acetone or chloroform, and insoluble -inwater or ether. Analysisgave 11.3% of .nitrogenlcompared-to vthe'theoretical calculated for CizI-I14O4Nz yof 11.2%.

:EXAMPLE L10 M on'oethyl ethanolamz'ne Morroethyl ethanolamine (45 g.) and diethyl carbonate (350 ml.) were placed in the apparatus describedV in Example 1 and the system was dried by distilling at 200 mm. pressure until 50 ml. of diethyl carbonate had been collected. Sodium methylate 1 g. was added, and'heating'wasoontinued'at vatn'rospheric pressure until l-58 m1. `of alcohol had Ibeenfobtainedl asfdistillate. Frac- 11.1328 1.4490; andan'oil, B."-P.'10'5"C. lat 1mm., 71152914308. The 3-'ethyl-2-loxazolidonewas soluble in water, giving asolution whichwas .neutral to litmus; the pure compound appeared to'be' hydrpscopic. Analysis -the newl compound gave 11.4% nitrogen,

compared to thertheoretical calculated for Theoil, 4BJP. 105.C.=at 1- Was.' the :ethyl carbonioV lester 1 of NeethyleN-(ihydroxyethyl) urethane: Y

v'Analysis egave .6.0% nitrogemuoompared Ato Ythe theoretical calculated. for-CioH-mOaN of 6.0%.

y "ExmvipneA 11 VMofnoethyz ethanolamine EXAMPLE 12 1Mo/no anbuty'lethanolamz'ne Mono-n-'butyl ethanolamine (58.5 .gD .dibutyl carbonate (102 g.) and tluene'(40 ml.) -were placed in theapparatus described in Example 1. The toluene was distilled off Vto dry the system. Potassium hydroxide (1 g.) was added as a. catalyst, and heating was continued at 690 mm. pressure, 70 ml. of butyl alcohol being obtained as distillate in 0.5 hour. The reaction mixture was ltered to remove the little solid matter present. Fractionation gave 3-n-butyl-2-oxazolidone, B. P. 94 C. at 1 mm., 11.13215 1.4515., The yield was 83% Analysis of the new compound gave 9.5% nitrogen, compared to the theoretical calculated for C'rHiaOzN 0f 9.8%.

EXAMPLE 13 Phenyl ethanolamzne Phenyl ethanolamine (68.5 g.), dibutyl carbonate (102 g.) and toluene (40 ml.) were placed in the apparatus described in Example 1, and the toluene was distilled off t-o dry the system. An-

hydrous sodium -carbonate (1 g.) was added, and

heating wasv continued at about 170 C. at atmospheric pressure. Butyl alcohol was formed rapidly, 90 ml. being collected as distillate in 0.5

hour. After cooling, the reaction product was dissolved in hot chloroform (150 mL), treated at the head of the column'. i The total alcohol obtained was 132 g. corresponding to 2.87 moles per mole of diethanolamine. Excess diethyl carbonate was removed from the reaction mixture by distillation under reduced pressure. The residue was a viscous oil Weighing 180 g. This was mixed with 50 ml. anhydrous alcohol and allowed to crystallize, yielding 46 g. of a solid product. The mother liquor was stripped of alcohol, and the residue was mixed with 100 ml. methyl alcohol and cooled in solid carbon dioxide.' A second crop of solid product weighing 28 g. was obtained, making a total of 74 g. The remainder of the material failed to crystallize.

The solid product was purified by recrystallization from alcohol. It melted at 10G-108 C., could not be sublimed, and was soluble in water, glacial acetic acid, hot alcohol, or hot chloroform. It was sparingly soluble in benzene, ether or diethyl carbonate.

From the method of synthesis, properties, and analysis of the new compound it was bis [2- (2-oxo-3-oxa`zolidyl) ethyl] iminodiethylene carbonate having the structure shown below.

with decolorlzing carbon, and allowed to crystallize. The product was Washed with petroleum ether. A total of 81 g. of S-phenyl-Z-oxazolidona M. P. 120-122.5 C., was obtained. Analysis of the product gave 8.3% nitrogen, compared to the theoretical calculated for Cel-1190211 of 8.6

EXAMPLE 14 Tris- (hydroymethyl) -aminomcthane Tris (hydroxymethyl) aminomethane (60.5 g.), dpropyl carbonate (76 g.) and toluene (100 ml.) were placed in the apparatus described in Example 1. The system was dried by distilling until l5 ml. of toluene had been collected. After Y addition of sodium methylate (0.5 g.) propyl alcohol was formed, and a mixture of it with toluene was taken oi as distillate. The residue remaining in the reaction iiask was a syrupy liquid which Was dissolved in hot water; the solution was ltcred and evaporated to dryness. The residue was purified by crystallization from acetone and then from anhydrous alcohol. The 4,4-di-(hydroxymethyl) -2-oxazolidone melted at 10Q-110 C.; it was soluble in water, giving a solution which was neutral to litmus.

A sample of product (0.5 g.) and benzoyl chloride (1.5 ml.) were heated together for 1.5 hours. The solid residue was heated with l0 m1. anhydrous alcohol to destroy excess benzoyl chloride, and puried by recrystallization fromA 95% alcohol. The benzoyl derivative melted at 175.5- 176 C.

EXAMPLE 15 Dietlianolamine Diethanolamine (105 g.), diethyl carbonate (300 m1,), and sodium methylate (0.5 g.) were placed in the apparatus described in Example 1. The reaction mixture was heated at atmospheric pressure until 96.5 g. of alcohol, B. P. 78-79" C., had been collected as distillate. Then fractionation was continued at 150 mm. pressure and 35.5 g. morealcoholic distillate was'collected at 50 C.

/C\ /CHZ Ol O Analysis gave 45.85% carbon, 5.38% hydrogen, and 9.96% nitrogen, compared to the theoretical calculated for CleHzsOioNs of 45.82%, 6.01%, and 10.01% respectively. The molecular weight found was 416 compared to the theoretical .of 419.

EXAMPLE 16 2-amino-Z-methyl-I-propanediol 2-amino-2-methy1-1,3-propanediol (52.5 g.) and diethyl carbonate (600 ml.) were placed in the apparatus described in Example 1. The reaction mixture was heated at atmospheric pressure by an oil bath at 150 C. The temperature of the liquid in the flask was 130 C. and 45 ml. of diethyl carbonate, B. l?. 123 C., were collected as distillate during 30` minutes. No alcohol was formed. After cooling somewhat, sodium methylate (1 g.) was added as a catalyst. Then heating was resumed and alcohol was fractionated Vout of the reaction mixture at reduced pressure.

ml. of alcohol were collected at 48.50 C. under 200 mm. pressure during 1.7 hours. This alcohol corresponded to 3 moles per moleof 2-amino- 2-methyl-1,3propanediol used as starting material. The reaction mixture was ltered to remove the trace of solid which had formed, and the excess diethyl carbonate was removed by distillation under reduced pressure. The residue was an oil which weighed g. It was soluble in Water, benzene, acetic acid, or ethyl acetate, but was insoluble in ether. It failed to crystallize and attempts to distill it resulted in decomposition.

ml.' of i' diethyl carbonate? werel collected asdistillate. No. alcohol was;formed.f Sodiummethe ylate (0.5 g.) was added'as.; a; catalyst; and', their 17 ml. 'ofV alcoholic distillate, B. 1.1.79.-817 C., were collected. Then the temperatureat therheadf of the column rose rapidly to the boiling point of diethyl carbonate. responds to onev moleper mole `of the. oxazolidone` used as startingv material.

had formed and excessV diethyl carbonate wasremoved by distillation .under reduced; pressure. The. residue; wasy anI voil whichzweghedlz en.. The

materiallappeared to be .entirely similar. to.;l then product described in the'rst paragraphcf-:thisf tem.Y Sodium methylate- (1 g.) wasadded as av catalystY andthe mixture washeatedy at 11G-126 C.' at atmosphericpressure WhileY 120 ml,A of alcoholv were -collected as distillates The alcohol obtained i corresponded to tour moles per mole' of the` tris-(hydroxymethyl)aminomethane. A- yellowish; taffy-likematerial separatedfrom the diethyl carbonate and wasremoved by ltration; it weighedf69 g. vAfter removal ofcxcess diethyl carbonate from .the motherA vliquor -by distillation? an Yoil remained asa residue. The products failedv to crystallize and decompo'sediwhenr sublimationwas attempted.l They were vpolymeric substances.

EXAMPLE4 I8-- V 2-amino-Z-'methxyZ-Ieproparlolk 2amino.2.,methyl1epropanol (8.9..g.`)., di..sec., butyl carbonate (1917s.), Xylene (100ml), and benzene (5.01Y m1.) were combined in .the apparatus Ydescribed. in Example 1. and,40. m1.' of. benzene werel distilled Voito vdrythe system.` Aj suspension of potassium .sec..butyl carbonate... (0.5. g.) in .25. ml. of sed-butyl alcohol .wasfaddedas'a..catalyst. The. saltv4 was prepared by dissolving. .potassium metalr invr sed-butyl alcohol. andsaturating. the solution with dry carbon .'dioxide. mixture:wasfthenheated at. atmospheric pres.- sure. vand. 149 of, sea-butyl .alcohol was. collected. as distillate duringY two.. hours. The. solvent, xylene., was: removed. by. distillation under 110 mm. pressure. The residue. remaining inthev reaction askwas. worked up for 4,4.-dimethy1-2 oxazolidone as in Example 2. The yield was.74

g., or 65% of theA theoretical.vv

EXAMPLE 19f Y v v Y d-Ephedmne .Tappan-ine` (8.25 g.) annxiyene.- (11o-mii were placedY in i. the i apparatus described in EX- ampleffl; 'Ihe systemwas "driedby-distilling; off" 20 ml'. ofxylene. under; 150 pressure. Di-npropyl carbonate (14.6 g.) was added; sodium methylatef(v.2:g. )was addedas a catalyst..and the.--reaction.mixture wasy heated for two hours. Propylalcohol (7 ml.) was collected asfdistillate, The solution remaining in the-flask was treated with decolorizing.l carbon. and then the` solvent was, removed .fbyr distillation1l under reduced .pressure; The f residueweighing. 9.8 g; solidiiied on The amount of alcohol cor The reaction mixture was ltered to remove thetracegof solid which The reaction cooling.

ether. The purified 3,4-dimethyl--phenyl-2- oxazolidone weighed g. and melted at (l2-92.5"T

V5 C, The compound wasfdextrorotatory [0:11335 y being.-+94.5. when 0.5385 g. ofthe substance was` made up to 25 m1. ofsolution with 95 alcolici.y

EXAMPLE 10 e dl-Norephedrine dl-Norephedrine (10 v g.), diethyl carbonate.

( g.), xylene (100 ml.) and benzene (25 m1.) were combinedin the apparatus described in Examplel, and the systeml was driedvby` distilling.-v

l5l until' the benzene hadlbeenremoved; After cool--l ingsomewhat, sodium methylate (0.3 g.) was.` added as a catalyst and heating was continuedv About 151 ml. of distillate1 were collectedwhich .contains afbout5.'7` ml. of alcohol.' The reaction mixturev at atmospheric pressure fory two hours.

' was distilled to drynessunder 50 mm; pressure.v The 'residue crystallized on cooling, Itwas dis solved in hot benzene and ltered to remove. in'-` The filtrate was evaporated:

organic impurities. to a small volumev and mixed with petroleum ether. The 4methyl'5-phenyl42-oxazolidone which crystallized weighed 9.7'g.l andmelted at?I 145-146 C. A mixturefof this product vvithvthe-V high melting -diastereomeric isomer, :described iny f Example-7, melted at 14s-146 C'.-

EXAMPLE v.2.1

2-amino-1-phenyl-I-propanol Z-amino-lf-phenyl-1-propanol (100 g.)

by distilling under 160 mm. pressure unti1j30 m l of'xylene hadbeencollected. Diethyl carbonate 40' addedand'heatingy Wasrthen continued atatmospheric pressure, 78ml. of alcohol beinglcollected lduring twohours. The. hot solutionremainingjnv thegreactionzashwas ltered and allowed to 455crysta-1lize. The solidproduct which separated melted. at 93400o C. and weighedv 865g.` The motherfliquor Wasyfreed of solvent by distillation andithereremained. 31.1' g. of a liquid residue.

. Theseproducts represent mixtures ofv thedi-` "astereomers of'4methyl5phenyl2eoxazolidone.- By `fractional crystallization of 'thesolid product` Attention is directed to my copending applica- K tions, Serial Nos. 648,206 and 648,208, filed concurrently herewith.

In View of the above, it will be seen that the several objectsof-the invention are achieved and other advantageous results attained.

As Ymany changes could be made in the above methods-and products withoutdepartingfrom thescope ofthe invention, it is intendedthat al1 mat- 76 ter-containedinthe above description shall bein--v ItY was washedwith petroleumy ether. and recrystallized from benzene and petroleum.

andr xylene ml) were'cornbined in the apparatus described-in Example 1, and the system was dried;

(91.5 g.) fand sodium-methylate (0.5 g.) e were 11 Y. terpretedas illustrative and not ln a limiting sense.

Iclaim:

1. The method of making 2-oxazolidones which are twice substituted in the ll-position which comprises mixing a -alkyl -amino alcohol in which the amino group is attached to a tertiary carbon atom, a dialkyl carbonate and an alkaline metallic compound catalyst under substantially anhydrous conditions, and condensing the moisture-free mixture to directly form a 2-oxazolidone.

2. The method of'making 2-oxazolidones which f are twice substituted in the Ll-position which comprises mixing a`-alkyl -amino alcohol in which the amino group is attached to a tertiary carbon atom, a dialkyl carbonate and an alkaline me- Y lyst, heating the resultant mixture under substantially anhydrous conditions to directly condense the amino alcohol and carbonate to form a 2- oxazolidone and to remoye alcohol formed by the reaction.

4. The method of making 2-oxazolidones which are twice substituted in the 4-position which comprises mixing a -alkyl -amino alcohol in which the amino group is attached to a tertiary'carbon atom, with a dialkyl carbonate, said mixture in'- herently containing moisture, heating the mixture to removesubstantially all of said moisture, adding an alkaline metallic compound catalyst to the moisture-free mixture, and heating the Vresultant mixture to directly form a 2-oxazolidone.

5. The method of making 2-oxazolidones which are twice substituted in the Ll-position which comprises mixing a -alkyl -amino alcohol in which the amino group is attached to a tertiary carbon atom, with a dialkyl carbonate, said mixture inherently containing moisture, heating the mixture under reduced pressure Vto remove substantially all of said moisture, adding an alkaline metallic compound catalyst to the moisture-free mixture, and heating the resultant mixture rat atmospheric pressure to directly form a z-oxazolidone.

6. The method of making 2-oxazolidones which are twice substituted in the 'Ll-position which comprises vmixing a -alkyl -amino alcohol in which the amino group is attached to a tertiary carbon atom, with a dialkyl carbonate, said mixture inherently containing moisture, heating the mixture to distill oi a minor proportion of the dialkyl carbonate with substantially all the moisture, addingas a catalyst an alkali metal alcoholate, andcondensing the resultant mixture to directly form a 2-oxazolidone.

'7. The method of making 2-oxazolidones which are twice substituted in the 4-position which comprises mixing a -alkyl -amino alcohol in which the amino group is attached to a tertiary carbon atom, with a dialkyl carbonate, said mixture inherently containing moisture, heating the mixture to distill off moist dialkyl carbonate under reduced pressure conditions, adding as a catalyst an alkaline earth metal alcoholate, and subjecting the mixture to distillation to directly -condense the amino alcohol and carbonate to form a z-oxazolidone and for continuously removing alcoholformedin thereaction.

8. The method of making 4,4-di`methyl-2-oxazolidone which comprises condensing 2-amino-2- methyl-l-propanol with'diethyl carbonate to directly form 4,4-dimethyl-Z-oxazolidone.

9. The method of making Ll,4dimethyl2-oxazolidone which comprises condensing 2-amino-2- methyl-l-propanol with dipropyl carbonate to directly form 4,4-dimethyl-2-oxazolidone.

10. The method of making 4,4-dimethyl-2- oxazolidone which comprises preparing an anhydrous mixture of 2-amino-'2-methyl-l-propanol and a dialkyl carbonate, said reagents inherently containing moisture, adding to the resultant mixture an alkaline metal alcoholate as a catalyst and heating the resultant mixture to directly form the 2-ox'azolidone and to distill oi alcohol formed by the reaction.

11. The method of making 4,4-dimethyl-2- oxazolidone which comprises mixing Z-amino-2- methyl-l-propanol with diethyl carbonate, said mixture inherently containing moisture, distilling the mixture under reduced pressure until a minor proportion of the dialkyl carbonate is removed with substantially al1 the moisture content of the mixture, adding as a catalyst for the resulting mixture sodium methylate and heating the resultant mixture under atmospheric pressure to directly form the 2-oxazolidone and to distill off alcohol formed by the reaction.

12. The method of making 4,4-dimethyl-2- oxazolidone which comprises mixing 2-amino-2- methyl-l-propanol with di-n-propyl carbonate, said mixture inherently containing moisture, distilling the mixture under reduced pressure until a minor proportion of the di-n-propyl carbonate is removed with substantially all the moisture `content of the mixtureQadding as a catalyst for the resulting mixture magnesium methylate and heating the resultantv mixture under atmospheric pressure to directly form the 2-oxazolidone and to distill ofi alcohol formed by the reaction.

13The method of making 4methyl4hy droxymethyl 2 oxazolidone which comprises condensing 2 amino 2-methyl-1,3propanediol with diethyl carbonate to directly form 4-methyl- 4-hydroxymethyl-2-oxazolidone 14. The method of making 4-methyl-4-hydroxymethyl 2 oxazolidone which comprises preparing an anhydrous mixture of 2-amlno-2- methyl-1,3-propanediol and a dialkyl carbonate, said reagents inherently containing moisture, adding to the resultant mixture an alkaline metal alcoholate as a catalyst and heating the resultant mixture to directly form the 2-oxazolidone and to distill oli alcohol formed by the reaction. Y

15. The method of making 4-methyl-4-hydroxymethyl 2 oxazolidone which comprises mixing 2-amino-2-methyl-1,3-propanediol with diethyl carbonate, said mixture inherently containing moisture, distilling the mixture under reduced pressure until a minor proportion of the dialkyl carbonate is removed with substantially all the moisture content of the mixture, adding as a catalyst for the resulting mixture sodiummethylate and heating the resultant mixture under atmospheric pressure to directly form the 2-oxazolidone and to distill ol` alcohol formed by the reaction.

16. 4,4-dimethyl-Z-oxazolidone. V

1'7. 4-methyl-4 hydroxymethyl-2-oxazolidone.

18. The method of making 4,4-dimethyl-2- 2,437,389 13 14 oxazolidone which comprises condensing 2- amino-Z-methyl-l-propanol with a dialkyl car- REFERENCES CITED bonate to directly form 4,4-dimethy1-2-oxazo1i- The following references are of record in the done, file of this patent:

19. The method of making 4-methy1-4-hy- 5 droxymethyl 2 oxa-zolidone which comprises UNITED STATES PATENTS condensing 2 amino-2-methy1-L3 propanedol Number Name Date with a dialkyl Vcarbonate to directly form 4- 2,215,038 Hedgins Sept. 17, 1940 methyl-4-hydroxymethy1-2-oxazolidone. 2,399,118 Homeyer Apr. 23, 1946 AUGUST H. HOMEYER. 10 

